1 files changed, 7 insertions, 0 deletions
diff --git a/check.py b/check.py
index 272e1394c..08c6f5887 100755
--- a/check.py
+++ b/check.py
@@ -577,6 +577,13 @@ if has_emcc:
         method = 'wasm-s-parser' # this is the default
       print method, ' : ', ' '.join(command), ' => ', success
       subprocess.check_call(command)
+
+      see_polyfill =  'var WasmJS = ' in open('a.wasm.js').read()
+      if method and 'asm2wasm' not in method and 'wasm-s-parser' not in method:
+        assert not see_polyfill, 'verify polyfill was not added - we specified a method, and it does not need it'
+      else:
+        assert see_polyfill, 'we need the polyfill'
+
       def break_cashew():
         asm = open('a.wasm.asm.js').read()
         asm = asm.replace('"almost asm"', '"use asm"; var not_in_asm = [].length + (true || { x: 5 }.x);')